System, method, and computer program product for transcoding or transrating video content for delivery over a wide area network

ABSTRACT

A system, method, and computer program product are provided for delivering video content over a wide area network (WAN). Included is at least one server for transcoding or transrating the video content for delivery over the WAN.

RELATED APPLICATION(S)

This application is continuation of U.S. application Ser. No.11/468,220, filed Aug. 29, 2006, which is incorporated herein byreference in its entirety.

FIELD OF THE INVENTION

The present invention relates to wide area network (WAN) communications,and more particularly to delivering video content over a WAN.

BACKGROUND

Many traditional television stations have expanded their services toprovide regular broadcast programming via the Internet. Unfortunately,such service often exhibits poor video quality and is unreliable. Forexample, during periods of great demand (e.g. during football/soccergames, popular primetime shows, breaking news, etc.), the service maybecome overloaded, and frame drops or complete service interruptions mayoccur.

Prior art FIG. 1 illustrates a system 100 by which traditionaltelevision stations provide broadcast programming over a wide areanetwork (WAN) such as the Internet. As shown, the system 100 includes acontent source 102 (e.g. a studio, pre-recorded programming, etc.) thatfeeds an encoder 104 which, in turn, encodes video content for thepurpose of broadcasting the same via a digital television transmitter106.

In addition to the foregoing infrastructure, the system 100 furtherincludes a plurality of computers 108, 110, 112, etc. adapted forreceiving the aforementioned video content. However, instead ofpreparing the video content for traditional broadcasting, the computers108, 110, 112 encode the video content for transmission over a WAN 114(e.g. the Internet, etc.) to one or more clients 116.

Unfortunately, as the number of clients 116 grows, the computers 108,110, 112 are unable to adequately support transmission of the videocontent over the WAN 114, particularly during the aforementioned periodsof great demand. As mentioned before, this results in undesirable framedrops, complete service interruptions, etc. There is thus a need forovercoming these and/or other problems associated with the prior art.

SUMMARY

A system, method, and computer program product are provided fordelivering video content over a wide area network (WAN). Included is atleast one server for transcoding or transrating the video content fordelivery over the WAN.

BRIEF DESCRIPTION OF THE DRAWINGS

Prior art FIG. 1 illustrates a system by which traditional televisionstations provide broadcast programming over a wide area network (WAN)such as the Internet.

FIG. 2 shows a system for delivering video content over a WAN, inaccordance with one embodiment.

FIG. 3 shows a system for delivering video content over a WAN, inaccordance with another embodiment.

FIG. 4 shows an example of delivering video content over a WAN.

DETAILED DESCRIPTION

FIG. 2 shows a system 200 for delivering video content over a wide areanetwork (WAN), in accordance with one embodiment. As shown, the system200 includes a content source 202. In various embodiments, the contentsource 202 may include a studio, a database of pre-recorded programming,a content server, and/or any other source of content, for that matter.

Further included is at least one server 204 for transcoding ortransrating video content for delivery over a WAN 206 to one or moreclients 208. Of course, the transcoding or transrating may be carriedout by the server 204 by performing such processing using its ownresources and/or resources under its control. For example, in oneoptional embodiment, such processing may be carried out utilizingspecialized transcoding/transrating hardware, video accelerationhardware, any other hardware or software, etc.

In the context of the present description, the WAN 206 may include anyone or more geographically dispersed networks. Just by way of example,such WAN 206 may include the Internet, in some embodiments. Of course,it is contemplated that the video content may or may not include audiocontent (or any other information, for that matter) as well.

In one embodiment, the transcoding may involve the conversion of thevideo content from a first format to a different second format. Forexample, in one optional embodiment, the content may be transcoded froma broadcast oriented format such as ATSC (HDTV signal), DVB-T or ISDB-Tto a format more suitable for computer network distribution, such asmpeg4, WM9, H.264, etc. Of course, such lists of formats are set forthfor illustrative purposes and should not be construed as limiting in anymanner as any format may be utilized. Further, in some optionalembodiments, the transcoding may involve the decoding of the firstformat, so that the video content may be re-encoded in the secondformat.

In other embodiments, the aforementioned transrating may refer to anyconversion that changes a bandwidth required for the delivery of thevideo content, but does not necessarily require any decoding toaccomplish the same. For example, in one embodiment, the transrating mayinclude parsing the video content, removing at least a portion of highfrequency components thereof, and then re-encoding the same. Of course,such example is set forth for illustrative purposes only, since anytransrating may be employed that meets the above definition. It shouldbe noted that the aforementioned server 204 may serve to transcode only,transrate only, or both transcode and transrate.

Further in the context of the present description, the server 204 mayrefer to any computer and/or processor. Also, the client(s) 208 mayrefer to a desktop computer, a lap-top computer, a personal digitalassistant (PDA) device, a mobile phone device, a television, anotherserver being served by the foregoing server 204, and/or any other devicecapable of receiving the video content for display or distributionpurposes. While the server 204 is shown to be separate from the contentsource 202 in FIG. 2, it should be noted that they may or may not beintegrated as a single component. Further, in an embodiment where theyare separate, they may be separated by a network (e.g. the WAN 206,etc.).

To this end, a manner in which the video content is delivered to theclient(s) 208 may be improved. More illustrative information will now beset forth regarding different embodiments including various optionalarchitectures and features with which the foregoing framework may or maynot be implemented, per the desires of the user.

For example, in various other performance-enhancing embodiments, one ormore of aspects of the content delivery may be adaptively selected basedon various factors (e.g. bandwidth, geographical location, historicalinformation relating to delivery of previous video content, at least oneaspect of at least one client receiving the video content, etc.). Stillyet, various applications of the foregoing system 200 involvingadvertising, time-shifted video content, etc. may also be employed instill other embodiments.

It should be strongly noted that the following information is set forthfor illustrative purposes and should not be construed as limiting in anymanner. Any of the following features may be optionally incorporatedwith or without the exclusion of other features described.

FIG. 3 shows a system 300 for delivering video content over a WAN, inaccordance with another embodiment. As an option, the present system 300may be implemented in the context of the system 200 of FIG. 2. Ofcourse, however, the system 300 may be used in any desired environment.Still yet, the above definitions apply during the following description.

As shown, a plurality of different types of content sources are providedincluding a first content source 302 and a second content source 303. Aswill soon become apparent, the first content source 302 receivesbroadcasted video content, thus using, as a content source, other remotecontent sources. Further, the second content source 303 may include theaforementioned studio or the like equipped for terrestrial transmissionand Internet-based broadcasting.

The first content source 302 includes one or more television tuners 304each adapted for receiving broadcasted video content (e.g. one or morelocally available programs, etc.) from one or more broadcasters via acorresponding broadcast channel. Such received video content may, inturn, be encoded via an associated encoder 306 into a format appropriatefor Internet transmission via an Internet router 308 which allows themultiple encoders 306 to share a high bandwidth connection to a WAN(e.g. Internet 310, etc.).

While multiple sets of tuners 304 and encoders 306 are shown in FIG. 3,it should be noted that an embodiment is contemplated where only asingle tuner 304, and/or encoder 306 is provided. In still anotheroptional aspect of such embodiment, one or more of such components maytake the form of a SLINGBOX or the like. In still other embodiments, asimple camera (not shown) may be provided with an associated encoder 306and/or router 308 for operating as yet another type of variant contentsource. In still additional embodiments, one or more encoder functionsassociated with the encoders 306 may be performed by a computer/serveror any other mechanism, for that matter.

By this design, the first content source 302 may be positioned at alocation where television programming of interest can be received andwhere a good connection to the Internet (e.g. multiple Mbit/sec/tuner,etc.) is available. For example, such location may include a networkedcorporate office, or in a special purpose location at a desiredgeographic site (e.g. U.K., India, China, etc.). To this end, a streamof digitally compressed video content may be sent to one more severs fortranscoding/transrating purposes, in a manner that will soon becomeapparent.

For further reasons that will soon become apparent, video contentavailable in an HDTV format may be transmitted in such original digitalformat without loss of quality (and without the need for encoding,etc.). Further, in other embodiments, video content available in astandard definition format may be encoded with a high quality encoder.In such embodiments, the HDTV formatted content may require an 18 Mbpsconnection, and the standard definition formatted content may require a2-6 Mbps connection. Thus, an Internet connection with 100 Mbps upstreambandwidth may transmit as many as 4-5 HDTV formatted steams or 20-50standard formatted streams, etc.

With attention now to the second content source 303, such source 303 isshown to include broadcast equipment 320 which may or may not be used inthe context of a studio and/or pre-recorded programming for generatingone or more channels of video content ready for broadcasting via abroadcast antenna 329. Similar to the first content source 302, thecurrent source 303 feeds the video content to an associated encoder 324for being encoded into a format appropriate for Internet transmissionvia an Internet router 326. In an embodiment where the second contentsource 303 broadcasts multiple channels, a set of the various componentsshown may be provided for each channel.

As an option, the broadcast video content may include advertisingtargeted towards a first (e.g. regional) audience reached by thebroadcast antenna 329. In such embodiment, a multiplexer 328 or the likemay allow insertion (into the Internet-based broadcast) ofadvertisements that target a second (e.g. worldwide) audience. Thelatter advertisements may include tourist advertising, advertisementsfor popular export goods, etc. To this end, at least one Internet-basedadvertisement may be delivered in addition to or instead of at least oneother regional broadcast-based advertisement.

With continuing reference to FIG. 3, one or more server farms 330A,330B, 330C are further provided. Each server farm 330A, 330B, 330Creceives the video content from geographically dispersed content sources(e.g. see, for example, the first and second content sources 302, 303,etc.) via at least one server 332 for various processing (e.g.transcoding, transrating, etc.) and subsequent routing by way of anInternet router 336. As an option, the video content may be stored bythe server(s) 332 utilizing at least one hard drive 334, for reasonsthat will be elaborated upon later.

In different embodiments, at least one of the server farms 330A mayinclude an intermediate server farm adapted for only delivering thevideo content to other server farms 330B, 330C which, in turn, deliversthe video content to an appropriate destination. Even still, at leastone of the server farms may include a terminal server farm (not shown)adapted for only delivering the video content directly to theappropriate destination. Of course, it is contemplated that at least oneof the server farms 330B, 330C may perform the functionality of both theintermediate and terminal server farms, in the form of a mixed useserver farm.

Thus, the exemplary hierarchical configuration shown in FIG. 3 includesa single intermediate server farm 330A for receiving video content fromthe sources 302, 303 and distributing the same to a plurality of mixeduse servers 330B, 330C. While such specific configuration is shown, itshould not be construed as limiting in any way. For example, otherconfigurations are contemplated with multiple layers of intermediateserver farms, some of which are for mixed use, terminal in nature, etc.

A plurality of different clients 340 are further illustrated in FIG. 3.For example, a plurality of personal computer clients 342 are included.Such personal computer clients 342 may use predetermined software toview the video content. In one embodiment, a first one of the personalcomputer clients 342 may have an 800 kbps bandwidth network connectionand therefore receive standard definition (SD) content with some loss ofspatial resolution. In other embodiments, a second one of the personalcomputer clients 342 may have 2 Mbps bandwidth connection, allowing fullsharpness SD content delivery.

Still yet, a plurality of television clients 344 are also included. Suchtelevision clients 344 may employ an IP-set top box (STB)-type device345A, 345B or the like to view one or more channels of the videocontent. In other embodiments, a digital media adapter (DMA) 345C may beused to fulfill similar useful functions needed for Internet TV service.In various embodiments, the television clients 344 may obtain the videocontent in HDTV or SD format, subject to the available Internetbandwidth. Strictly as an option, one or more of the television clients344 may employ a computer 346 for receiving the video content over theInternet 310, but then views and selects the content via the televisionclient 344 utilizing a digital media adapter or the like.

In various embodiments, the personal computer clients 342 may firstreceive the video content in a window, and then switch to “full screenview,” if desired. Further, the personal computer clients 342 may use auser interface (UI), including extensive keyboard/mouse input, to selectand/or search various content sources. This may, in one embodiment, bereferred to as a “2 foot UI.” In contrast, the television clients 344may use a remote control device to select content for viewing, withoutnecessarily employing keyboard/mouse input (and hence with limited or notext input capability, etc.). Such television clients 344 may navigate amenu or program guide services to select the desired video content, orjust “surf” channels. This may be referred to as a “10 foot UI.” Thesystem 300 may be used for either UI method or other UI methods, forthat matter.

FIG. 4 shows an example 400 of delivering video content over a WAN.Specifically, the present example 400 may be carried out in the contextof the system 300 of FIG. 3. Of course, however, the example 400 may becarried out in any desired environment. Again, the above definitionsapply during the following description.

As shown, included in the present example 400 are a content source 402(e.g. see the first content source 302 of FIG. 3, etc.), at least oneintermediate server 404, at least one mixed use or terminal server 406,and at least one television client 408 and computer client 410. In use,a signal received by a tuner 412 of the content source 402 is firstencoded into compressed digital video, utilizing an encoder 416. In asituation where the video content received by the tuner 412 is alreadydigital, no encoding is necessary.

The encoded video content may then be sent to the intermediate server404. In some embodiments where Internet bandwidth at the content source402 is limited, the video content may be sent to a single intermediateserver 404 which, in turn, forwards it to one or more mixed use orterminal servers 406. While not shown, additional layers of intermediateservers 404 may be provided to scale for more users. To this end,streams of video content may arrive at one or more terminal servers 406from where they are sent to the appropriate client 408, 410

As mentioned earlier, various aspects of the system may be adaptablebased on various factors. Specifically, any one or more of aspects ofthe delivery may be adaptively selected based on various factors (e.g.bandwidth, geographical location, historical information relating todelivery of previous video content, at least one aspect of at least oneclient receiving the video content, etc.).

Such aspects of the delivery may relate to which of a pluralitydifferently formatted content copies to utilize for delivery of thecontent, which of a plurality geographically dispersed servers (andcontent thereof) to utilize for delivery of the content, a number ofcontent copies to be made and where they are to be stored, whether totranscode/transrate or not, what type of transcode/transrate algorithmto use, how to divide video history across servers/disks of a particularcontent source, what advertisement content to deliver, and/or any otheraspect of the delivery, for that matter.

To support one embodiment where differently formatted content copies areselected in a manner that will soon become apparent, several versions ofthe video content may be created by the intermediate server 404 bytranscoding/transrating the same. For example, a video content in anHDTV format may be transcoded to a SD format. A SD format (or even HDTVformat) may also be transcoded to an even more compact resolution formatto serve clients with low Internet connection speed. It is also possiblethat an HDTV format (e.g. MPEG-2, etc.) may be transcoded to a morecompact HDTV digital compression format, such as MPEG-4, AVC, etc.

Thus, in one exemplary adaptable embodiment, the system may address thefact that the clients 408, 410 may have dramatically different networkbandwidth, ranging from a few hundred kbps to 100 Mbps. In suchembodiment, the appropriate terminal server 406 may choose theappropriate version of video content available from the intermediateserver 404. For instance, for clients with a high bit rate connection,the HDTV formatted version may be chosen. Further, for clients with amedium bit rate connection, the SD version may be utilized. Still yet,for users with a low bit rate connection (or with small screenresolution), a lowest resolution version may be chosen.

In additional embodiments, the terminal servers 406 may dynamicallyobserve the effective bandwidth at which reliable communication withclient 408, 410 is possible, and transrate the video content to exhibita bit rate suitable for reliable delivery to that client 408, 410. Tothis end, a single terminal server 406 may serve multiple clients 408,410 which each, in turn, receive a different bit rate, differentresolution, and/or different video content.

In still additional embodiments, the video content may be time-shifted.For example, the video content may be stored (e.g. by any of theservers, for example), thus making the video content available afterbeing broadcasted. In one embodiment, this may be accomplished bydelaying the video content by a fixed amount to compensate for adifference in daylight time between source and a particular client. Inother embodiments, this may be accomplished by allowing the client 408,410 to view programs already transmitted within a predetermined amountof time (e.g. anything transmitted anywhere in the world within the lastweek, day, etc.). Of course, some broadcast content of a more permanentnature (e.g. movies, premium content, etc.) may be stored indefinitelyfor being made available on an on-demand basis. This feature may furtherallow for viewing at an appropriate time in light of a time zone inwhich the viewer is located, etc.

To accommodate the foregoing time-shifting or any other desiredfunctionality, the storage of the video content may occur anywhere onthe network, either close to the content source 402, the terminalserver(s) 406, etc. Further, the location where a particular piece ofvideo content is stored, and how many copies are stored may beadaptively selected based on expected behavior. Such expected behaviormay, in turn, be based on historical information (e.g. collectedregarding previously observed behavior, etc.). To this end, the videocontent may be available from an optimal number of optimally-locatedservers for facilitating an effective delivery of broadcast content.

In still another embodiment, a single copy of video content may bestored for each content source in an original format at a firstintermediate server 404 where the content gets delivered. While this maybe the most cost effective technique, hard disks on which the content isstored and/or the server to which such hard disks are attached maybecome a bottleneck, if many clients 408, 410 attempt to access thevideo content from such intermediate server 404.

To prevent such bottlenecking, each intermediate server 404 may bedimensioned to handle a required number of terminal servers 406. In someembodiments, the video content of the past week of a given contentsource may be distributed over multiple disks (e.g. 1 day back onserver/disk A, 2-days back on server/disk B, etc.). This, in turn,distributes the traffic caused by the clients 408, 410 requesting apopular station over many disks without causing duplication of storage.

Thus, the decision as to where to store the video content, how manycopies to store, and how to divide video history across servers/disks ofa particular content source may be made based on expected trafficpatterns and/or any other of the aforementioned factors, in order tominimize the probability of creating a bottleneck, while preventingexcessive duplication.

As mentioned previously, a variety of applications may be employedutilizing the foregoing embodiments. For example, intelligentadvertising may be employed, whereby one or more servers utilizeinformation (e.g. location, profile, user input, etc.) about/from theclient/user to tailor advertisement content for such client/user. Stillyet, other embodiments are contemplated involving click-throughadvertising, etc. where interaction between the client/user and one ormore servers may be tracked, logged, etc. and used for providingadditional functionality (e.g. rewards, surveys, etc.).

By this functionality, various embodiments are therefore provided with acost proportional to a number of simultaneously active users, andlargely independent of an amount of video content. Such embodiments maybe augmented by adding additional terminal and/or intermediate serverfarms, as required. By this design, television stations may be able toreach a worldwide audience without necessarily creating bottlenecks thatmay cause service drops in periods of great demand. These embodimentsfurther allow many of such television stations to share equipment,reducing overall infrastructure cost. To this end, the embodiments maybe scalable and used to create a worldwide television distributionsystem that is capable of transmitting SD and HDTV content from many orall television stations in the world to a multiplicity of worldwideusers.

In different optional embodiments, the foregoing embodiments may bedeployed in any desired manner. For example, a small scale service maybe deployed using a single mixed use server in a trial metropolitanregion. As a number of clients/users grow, more levels of intermediateservers and terminal serves may be added in locations with highbandwidth connectivity with respect to the region of clients/users thatare served. If such intermediate/terminal services are placed close tolarge user communities, Internet traffic may thereby be partitioned suchthat no bottleneck exists, permitting a system to grow as large asdesired. Graceful degradation thus may automatically occur in periods ofpeak demand, where adaptation to observed bandwidth automaticallyreduces bit rate and hence video spatial resolution, but frame drops ortotal loss of service may be avoided, in such embodiments.

While various embodiments have been described above, it should beunderstood that they have been presented by way of example only, and notlimitation. Thus, the breadth and scope of a preferred embodiment shouldnot be limited by any of the above-described exemplary embodiments, butshould be defined only in accordance with the following claims and theirequivalents.

What is claimed is:
 1. A system, comprising: at least one intermediateserver for: receiving a plurality of portions of video content from asource over a predetermined period of time; and for each of the portionsof the video content: determining a portion of the predetermined periodof time during which the portion of the video content was received;selecting one of a plurality of additional servers according to theportion of the predetermined period of time during which the portion ofthe video content was received; and distributing the portion of thevideo content to the selected one of the additional servers; whereineach of the additional servers is associated with a different portion ofthe predetermined period of time, such that: a first one of theadditional servers that is associated with a first portion of thepredetermined period of time is selected for distributing theretoportions of the video content received during the first portion of thepredetermined period of time, and a second one of the additional serversthat is associated with a second portion of the predetermined period oftime is selected for distributing thereto portions of the video contentreceived during the second portion of the predetermined period of time.2. The system as recited in claim 1, wherein the at least oneintermediate server is one of a plurality of distributed servers in thewide area network.
 3. The system as recited in claim 2, wherein thedistributed servers are positioned at locations different from alocation of the source of the video content.
 4. The system as recited inclaim 2, wherein the distributed servers include at least one firstserver for transcoding the video content.
 5. The system as recited inclaim 4, wherein the video content is transcoded into different formats.6. The system as recited in claim 5, wherein the different formatsinclude different resolutions.
 7. The system as recited in claim 4,wherein a plurality of copies of the video content are stored each witha different format.
 8. The system as recited in claim 5, wherein the atleast one intermediate server delivers the video content in thedifferent formats to the additional servers.
 9. The system as recited inclaim 8, wherein the least one first server, the at least oneintermediate server, and the at least additional servers arehierarchically configured.
 10. The system as recited in claim 8, whereinthe additional servers deliver the video content to a client.
 11. Thesystem as recited in claim 9, wherein the additional servers select fromthe different formats for delivery of the video content to the client.12. The system as recited in claim 11, wherein the additional serverstransrate the video content for delivery to the client.
 13. The systemas recited in claim 1, wherein the video content includes video contentreceived via a plurality of broadcast channels and transmitted to the atleast one server for delivery over the wide area network.
 14. The systemas recited in claim 1, wherein the portion of the video content isdistributed to the one of the additional servers selected according tothe portion of the predetermined period of time during which the portionof the video content was received such that network traffic caused bymultiple clients requesting the video content is distributed withoutcausing duplication of storage.
 15. The system as recited in claim 1,further comprising at least one server for transcoding or transratingthe video content for delivery over a wide area network.
 16. The systemas recited in claim 15, wherein the at least one server is one of aplurality of distributed servers in the wide area network.
 17. Thesystem as recited in claim 16, wherein the at least one server thattranscodes or transrates the video content is positioned at a locationdifferent from a location of the source of the video content.
 18. Thesystem as recited in claim 15, wherein the system operates such that thevideo content is time-shifted as a function of a time zone in which aclient receiving the video content is located; and wherein the systemoperates such that at least one aspect of the delivery relates to whatadvertisement content to deliver based on a particular audience andtransmission medium, such that a first advertisement is delivered withthe video content for receipt by a regional audience via a broadcast,the first advertisement targeted towards the regional audience reachedby a broadcast antenna, and a second advertisement is delivered with thevideo content instead of the first advertisement for receipt by aworldwide audience via the wide area network, the second advertisementtargeted towards the worldwide audience reached by the wide areanetwork.
 19. A computer program product embodied on a computer readablemedium, comprising: computer code for receiving a plurality of portionsof video content from a source over a predetermined period of time; andfor each of the portions of the video content, computer code for:determining a portion of the predetermined period of time during whichthe portion of the video content was received; selecting one of aplurality of additional servers according to the portion of thepredetermined period of time during which the portion of the videocontent was received; and distributing the portion of the video contentto the selected one of the additional servers; wherein each of theadditional servers is associated with a different portion of thepredetermined period of time, such that: a first one of the additionalservers that is associated with a first portion of the predeterminedperiod of time is selected for distributing thereto portions of thevideo content received during the first portion of the predeterminedperiod of time, and a second one of the additional servers that isassociated with a second portion of the predetermined period of time isselected for distributing thereto portions of the video content receivedduring the second portion of the predetermined period of time.
 20. Amethod, comprising receiving a plurality of portions of video contentfrom a source over a predetermined period of time; and for each of theportions of the video content: determining a portion of thepredetermined period of time during which the portion of the videocontent was received; selecting one of a plurality of additional serversaccording to the portion of the predetermined period of time duringwhich the portion of the video content was received; and distributingthe portion of the video content to the selected one of the additionalservers; wherein each of the additional servers is associated with adifferent portion of the predetermined period of time, such that: afirst one of the additional servers that is associated with a firstportion of the predetermined period of time is selected for distributingthereto portions of the video content received during the first portionof the predetermined period of time, and a second one of the additionalservers that is associated with a second portion of the predeterminedperiod of time is selected for distributing thereto portions of thevideo content received during the second portion of the predeterminedperiod of time.
 21. The system as recited in claim 1, wherein thedifferent portions of the video content received over a predeterminedperiod of time from the source are distributed to different additionalservers according to a portion of the predetermined period of time inwhich each of the portions of the video content were received from thesource, to distribute network traffic caused by multiple clientsrequesting the video content without causing duplication of storage, by:identifying a first portion of the video content received over the firstportion of the predetermined period of time from the source; deliveringthe identified first portion of the video content to the first one ofthe additional servers associated with the first portion of thepredetermined period of time; identifying a second portion of the videocontent of the given source received over the second portion of thepredetermined period of time from the source, the second portion of thepredetermined period of time different from the first portion of thepredetermined period of time; and delivering the identified secondportion of the video content to the second one of the additional serversassociated with the second portion of the predetermined period of time.